Built-up cutting tool



J. LONG.

BUILT-UP CUTTING TOOL.

APPLICATION HLED 020.22. 1919.

Patented Mar. 7, 1922.

ATTORNEY FIGQ PATENT OFFICE.

JAMES LONG, OE COVENTRY. ENGLAND.

BUILT-U1? CUTTING TOOL.

Specification of Letters Patent.

Patented Mar. 7, 1922.

Application filed December 22. 1919. Serial No. 346,658.

To (ZZZ w 7mm it may concern Be it known that I. Janus Lone, a subjectof the King of England. residing at Coventry, in the county of Warwick,England, have invented certain new and useful Improvements in Built-UpCutting Tools, of which the following is a specification.

This invention relates to built-up milling cutters, reamers, and thelike of the type in which the body portion is provided withlongitudinally disposed grooves in which the cutters are held and havecontact with their side and bottom portions, and it has for itsprincipal object to provide improved means for securing the blades inthe bodies of the cutters, and, in the case of reamers, to provide forappropriate movement of the blades in the bodies to constitute an ad.-justable or expansible cutting tool.

According to this invention the body of the cutter has formed in itgrooves of uniform dovetail cross-section, (the wider por tion nearestthe centre of the body), that is to say, grooves whose bottom edges areparallel to one another and whose sides are of a constant width apartalong lines parallel with their bottom edges, and in these grooves thecutters are held by a wedge-action. Where it is desired to secure thecutter against movement or subsequent adjustment, such wedge action maybe obtained by giving the cutter throughout its length only such adegree of taper as is required to ensure a driving fit in the groove.

For an adjustable reamer the depth of the grooves progressivelyincreases from the end of the reamer body, and a wedge is employed sideby side with the cutter and is adjustable lengthwise of the groove. thecombined cross section of cutter and wedge being such as to fit thegroove uniformly from. end to end. Upon'the end faces of the cutters andwedges collectively, bears (preferably by the agency of a washer), anadjusting nut, screw threaded upon the body of the reamer. By thisarrangement the adjusting means are confined to one end of the reamer sothat at the other end the cutters can project from the body clear of allobstructions to constitute an end or bottom reamer- The manner ofcarrying out the invention as applied to an adjustable reamer is shewnin the accompanying drawings, in which,--

Figure 1 is a side elevation, r

, Figure 2 is a central longitudinal section through the body of thereamer,

Figure 3 is an end elevation on a larger scale than the foregoing views,

Figure 4:, also to alarger scale, shews a plan of the combined cutterand wedge, of which Figure 5 is an end view, and

Figure 6 shews a perspective view of a modified. detail of construction.

Like letters indicate like parts throughout the drawings.

Formed in the parallel sided body A of the reamer are longitudinallydisposed grooves A adapted to receive the cutters B and wedges C. Thedepth of these grooves A uniformly increases from end to end, as shewnin Figure 2, their sides converging to one another at the upper part ofthe groove to give to it a dove-tail cross section.

It is to be understood that in forming these grooves theirCIOSS-SGCCIOII is, with reference to their bottom surface, uniform fromend to end, that is, their bottom edges are parallel to one another andtheir sides are of a constant width apart along any lines parallel totheir bottom edges, but, obviously, by reason of their graduallyincreasing depth, the width at the upper edges of the grooves (as seenin Figure 1) diminishes as the depth of the grooves A? increases.

The manner of forming the grooves A is preferably such that the angle Xwhich each side of thegroove makes with the contiguous part of thebottom is a right angle. not only facilitates fitting the cutters B andwedges C in the grooves. but also avoids the necessity for acutting-tool of special form, it being thus possible to use an ordinarysides-and-face type milling cutter in the manner hereunder described,which thus gives rise to the particular form (i. e., a fld-t tened Vform) of the bottom of the groove as shewn in the drawings. Obviously,how- This.

ever, if desired the bottom of the grooves A the same tool, afterresettingv the reamer body in the machine so that one of the side wallsof the groove just formed will be remit to constitute with the opposites de of the groove a dove-tail cross section. As re sult of this, thefinished groove A has two faces at the bottom part, inclined to oneanother but each at right angles to its adjacent side of the groove. Incross-section one side a of the groove is substantially parallel to aradial line extending from the centre of the reamer body to a positionmidway between the top edges of the groove. while the other side of thegroove is inclined considerably to the radial line aforesaid. Againstthis latter side and the adjacent bottom surface ofthe groove therespective faces B and B of the cutter B, which has in all four faces,closely fit. Preferably some clearance (not shewn) is provided betweenthe next face B of the cutter and the adjacent face of the bottom of thegroove, so that only the right-angled surfaces B B require fitting.

The last face B of the cutter is adapted to co-operate with the inclinedface C of the wedge (l. (which latter is of rectangular cross-section),in such manner that when the cutter B and wedge C are together insertedin the groove A they bear upon the bottom thereof and closely fit thesides from. end to end of the groove.

It will be seen by reference to the drawings that the action of thewedge C is to thrust the cutter B firmly against the side andbottom ofthe groove A and the clearance given to the side B of the cutter, asabove mentioned, ensures this actlon taking place.

The edge B of the cutter B stands above the edges of the groove A -toform the cutting edge of the reamer, and the wedge C is adjustablelengthwise of the groove.

The inner end of the reamer body A is reduced somewhat in diameter andis screwthreaded over a portion A of the so reduced part, the remainingpart A between the screw threaded part and the body A being left plain.The grooves A? are prolonged into this screw threaded part A3, and thecutter B and wedgeiC are of a length to extend beyond the end of theplain. part A. into the screwed part A by an amount equal to thatrequired for theirrange of adjustment lengthwise. V

The inner ends of the cuttersand wedges aresquared off so that they canbe uniformly acted uponby an adjusting nut D carried upon thescrew-threaded part A? and provided with slots D or the like by, whichit can be rotated, a washer orcollar E being r inserted between thecobperating faces of the nut and cutters. To prevent rotation of thecollar E during adjustment of the nut D, slots Eflor the like may beprovidedfor engagement by a spanner, or. if desired, a

pin or feather might be provided on the inner periphery of the washer toengage a. groove in the reainer body.

It will be apparent that when the rearner is adjusted by thelongitudinal movement of the cutters, their cutting radius will beincreased in accordance with the longitudinal inclination of the bottomof the groove to the axis of the reamer.

As the adjustment acts positively in one direction only, that is toincrease the. cutting radius, it is evident that adjustment in thereverse direction can be accomplished by simply slacking back the: nut Das far as required and tapping on the outer ends of the cutters andwedges to return them against the face of the collar E.

means of the wedge any required degree of tightness of fit of the cutterB can be obtained in the groove A As the latter is of uniform sectionthroughout its length, no changein the fit will takeplace duringadjustment of the reamer, provided. no .rel ative movement of cutter andwedge occurs during such adjustment. Such relatlve movement is avoidedby accurately squaring off the innerends of the cutter and wedge afterthe latter have been adjusted to a correct fit in the groove, so thatthey may both move together under the action of the nut An importantfeature in this vmethod of fitting the cutters is the ability to takeup, by means of the wedge, any slackness of the cutter due to prolongedwear. After such, 95 adjustment for wear it will be obvious that the endsurfaces of the cutter and'wedge must again bemade flush with oneanother, as when originally squared off in the first instance. Ininserting the wedge and cutter in the groove it is obviously preferablethat the thin end of the wedge should be towards the adjusting nut D sothat after adjust ment the wedge, instead of the cutter re quires facingoff. i i

To prevent the wedges being drawn from the grooves, if the reamer gripsfast in use and has to be pulled endwiseto 'free it, screws F may besunk in the body A, to en gage with their heads the elongated notches C?formed in the outer edgeof the wedges C. This screw F would; require tobe slacked back somewhat when the reamer'was eX- panded to allow for theresultant rise of the wedge in the groove. r 1

If desired, in place of the plain collar or washer E, the modified form,G, 'Figure'tl. may be employed. This is provided with projections Gadapted to enter the grooves A thus preventing its relative rotation on120 the reamer. These projections G may also be extended at G from oneof the end faces of the collar tobear on the ends of the cutk ters andwedges,their length being made equal to the'amount of thelongitudinalad- 125 justment provided for the cutters B'. .By thisarrangement only, the threaded part A of the reamer body need be reducedbelow the diameter ofthe body A, and thusthe parts of the cutterswhichwould otherwise 130 lie in the reduced part A*"'(see Figure 1) canbe as well supported as those portions which lie in the part A.

A special feature of this adjustable reamer is that the adjusting meansare confined to one end of the cutter, so that at the other end thecutters can project from the body clear of all obstruction, toconstitute an end or bottoming reamer.

Furthermore, it will be apparent that by this invention the cutter canbe firmly se cured along the whole length of the groove by means whichare entirely independent of the adjusting device, and that these meansensure the cutter being always thrust against the bottom of its groove,a condition essential to precise adjustment.

By reason of the wedge section of the cutters, those parts which projectfrom the end of the body possess great lateral stiffness so that thetendency of their cutting-edges to chatter is thereby minimized.

here the invention is applied to built-up milling cutters or the like,the cutters may be firmly secured by means of wedges employed on thegrooves as above described. Alternatively, the wedges may be omitted, byfitting the cutters to the grooves and giving to the former justsufficient taper to ensure a driving fit to locate it in position.

What I claim as my invention and desire to secure by Letters Patentis 1. A reamer comprising a body part having out lengthwise therein agroove of uniform cross section with a wide bottom, one ofthe side wallsof the groove being parallel to a radial line extending from the centerof the said body part midway between the top edges of said groove andthe other side wall being inclined to the said radial line, the anglesformed by the said side walls with their contiguous bottom part beingboth right angles; the cutter closely fitting the one side wall andbearing on the bottom of the said groove.

2. In a. reamer as specified in claim 1, a wedge arranged adjacent thestraight side wall between the latter and the corresponding straightside of the cutter, the combined cross-section of the said cutter andwedge being uniform and fitting the two sides of the groove from end toend.

3. A reamer as specified in claim 1, in which between the cutter and theother side wall a wedge is arranged and in which the grooveprogressively inclines toward the cutter-axis from the forward end ofthe body part toward its rear end, the body part having a reducedportion where the groove approaches the cutter-axis, the cutter andWedge protruding from the groove beyond said reduced portion, and anadjusting nut being screw-threaded on the said reduced portion so as tobear on the ends of both the cutter and wedge and act thereonsimultaneously.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JAMES LONG. Witnesses:

ALBERT BROWN, ANNIE L. WADE.

